Contamination of St. Lawrence River sediments by DDD applications at EXPO 67

My current research includes a collaborative project with Valerie Langlois (RMC) on the toxicity of diluted bitumen to native fish species of Canada and the identification of molecular markers of oil exposure and effects. Research funded by an NSERC Strategic Grant with Ana daSilva (CIVL – PI) and co-PIs Stephen Brown (CHEM, SES), Kevin Mumford (CIVL) and Allison Rutter (ASE, SES) and supported by Environment Canada and Northwest Hydraulics Inc is investigating the potential role of hyporheic flows in transporting oil droplets from surface waters of rivers into bed sediments where fish spawn. Hyporheic flows are currents of water that move through porous gravel sediments due to pressure gradients caused by the flow of rivers over uneven bottom features of rivers. Julie Adams, a PhD student in Environmental Studies, is investigating the toxicity to fish embryos of petroleum hydrocarbons that dissolve from stranded oil droplets in sediments, and developing exposure models that can replicate sediment oil contamination in rivers.

My past interests included the role of metabolism in chemical toxicity to fish, with a focus on the reactive by-products of polycyclic aromatic hydrocarbon (PAH) metabolism by liver mixed function oxygenases enzymes (i.e. the cytochrome P450 or CYP1A enzymes). The goal was to understand the mechanism of PAH toxicity to the early life stages (embryos and larvae) of fish and the consequences for larval survival and recruitment. Research on mechanisms includes the role of alkyl substitution in the toxicity of petrogenic PAH, the identification of which PAH in crude and refined oils are toxic to fish, and how chemical dispersion of oil controls exposure to petrogenic PAH. The results are directly applicable to ecological risk assessment of PAHs from oil, coal tar, creosote, soot and the by-products of microbial degradation of resin acids from pulp mill effluents. I have also been involved in studies of the transfer of mercury from point sources and from contaminated sediments through aquatic food webs of the St. Lawrence River, the contamination of St. Lawrence River sediments by pesticides used at EXPO 67, and the potential role of chemical contamination in the declining abundance of American eel in Lake Ontario.

Past research has been supported by grants from the Natural Sciences and Engineering Research Council (NSERC), the Ontario Ministry of the Environment's Best in Science program, and research contracts from the Canadian Offshore Oil and Gas Environmental Research (COOGER) centre, Department of Fisheries and Oceans. These grants facilitated collaboration with other scientists at Queen’s, the University of Waterloo, the Université de Québec à Rimouski, the University of Maine, the University of Jyvaskyla and the University of Joensuu in Finland, with Environment Canada and the Department of Fisheries and Oceans (DFO), and with the US National Oceanic and Atmospheric Administration.

Service

Invited Member of a Royal Society of Canada Expert Panel on The Behaviour and Environmental Impacts of Crude Oil Released into Aqueous Environments, January 13, 2015-June 30, 2015.